Manchester coding has long been popular for low-cost short distance data communication applications despite its inefficient use of bandwidth. In one application, Manchester coding is used in some local area networks to provide data transmission over an unshielded twisted pair cable. The coder's most desirable property is the presence of a zero crossing in the center of every bit period. This property permits both low-cost clock timing recovery and very fast start-up from a no signal condition. The latter benefit is particularly important in multiple user configurations such as local area networks.
Commercially available Manchester receivers operate by sampling the received signal at either one-quarter bit before or after mid-bit time period. Because of the popularity of Manchester coding for data transmission, there is a continuing need to improve the signal-to-noise (S/N) ratio of the received signal and reduced intersymbol interference.